Ignition apparatus



July 9, 1929( w T 1.720.540

IGNITION APPARATUS Filed March 24, 1928 v 7 aaozmqs pressure characteristic of l atented July 9, 1929.

rrnn STATES PATENT. OFFICE.-

WELLMM A... UHRYST, OF DAYTON, OHIO, ASSIGNOB TO DELOO-REMY CORPORATION,

OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

IGNITION nrrnnn'rus.

Application filed. March 24,

This invention relates to ignition apparatus ilor internal combustion engines and particularly to means for controllin the timing of the ignition spark in accor ance with the the combustion of the fuel charge in the engine. In the type of ignition controlling apparatus to which the present invention is related, the timing of s the ignition spark is varied in. accordance W with the position of a displacement member such as a piston movable within a pressure chamber, such as a cylinder, and sub ected to combustion pressure impulses which occur at predetermined successive intervals during combustion and which are alternately against o posits ends of the displacement member.

ll onsequently the position in which the displacement member is located relative to the displacement chamber is dependent upon the dililerential between the successive combustion pressures which are applied alternately to opposite ends of the displacement member.

In devices of this sort the pressure chamber is in direct communication with the combus;

25 tion chamber of the engine and is therefore subjected to considerable heat. It-is one of the objects of the present invention to provide a combination ignition timer and controller oi the type referred to, .in which the as controller will reliably operate notwithstanding the temperature to which it may be subjected and particularly'to provide for such lubrication of the controller as will withstand high temperature.

A. ilurther object of the invention is to simplify the valve mechanism which controls the successive admission of pressure to opposite sides or ends of thedisplacement member.

Further objects and advantages of the present invention will he apparent'lroni the the following description, reference being had to the accompanying drawing, wherein a preferred form of embodiment of the present invention is clearly shown.

lln the drawing:

Figfil. is a longitudinal sectional view oi an ignition apparatus embodying the present in vention, and Fig. i is a fragmentary plan 5% view oil the ignition interrupter.

Fi Q is a sectional view onthe line 2--% oil 3 is oi l ig. a

lid.

a sectional view on the line 3--3 hates the ignition timer 1928. Serial m5. 264,804.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3.

Fig. 5 is a pressure-time indicatondiagram of a conventlonal four-stroke cycle internal combustion engine and illustrates the manner of controlling the displacement member of the ignition timer controller in accordance with impul'ses occurring at predetermined successive intervals during the explosion of fuel charge in the combustion chamber of the engine.

It is well known that the ignition timer is a periodic circuit closer which is operated by a shaft driven by the engine. The circuit closer operates to close the circuit which includes an induction coil and a source of current in order that the coil may be energized while the circuit is closed, and then operates to break the circuit of the ignition coil so that its energy may be suddenly-dissipated to produce a sparking impulse which is transformed to high voltage through the aid of the secondary coil of the induction coil. H the time relation between the openingof the ignition primary circuit and the engine cycle of operations is varied, it is apparent that the timing of the ignition s ark will be varied. The variation between t e engine cycle and the o eration of the circuit interrupter may be e ected in difierent ways. In the present invention in Fig. 1, I show means for varying the angular relation between the ignition timer cam and the shalt which is connected with the engine tor the purpose of driving the cam. iln the drawings desigdrive shaft which is supported by suitable bearings 21 and 22 provided in the tubular shank 23 in the igni tion timer frame 24:. The'ignition interruph er is housed within a cup-shaped housing or timer cup 25 supported by the trains 241- and attached thereto in any suitable manner. e ignition interrupter includes an engine op erated cam 80 having lobes which are engageable with a rubbing block 31 attached to a circuit brealrer lever 32'which is pivotally supported at 33 upon. a stud 3t carried by plate 35 attached to the cup Q5. it current conducting leaf-spring member 36 conducts current llrom a terminal notch she to the lever and yieldingly urges the rubbing block 31 toward thecam 3d and a movable contact 37 carried by the lever ddtoward a stationlldd lllli ary contact 38 carried by supporting bracket attached to a short shaft 40 journalled in a bearing 41 and having its lower end received by a recess 42 in the tubub lar upper end 43 in the shaft 21. The tubular end 43 is provided with diametrically opposite oblique slots shown at 44 in Fig. 1. The slot 44 receives a cross pin 45 which extends also through a longitudinal notch 46in the shaft 40. The cross pin 45 is supported at its ends by a grooved collar 47, which is adapted to be shifted by bifurcated lever 48 attached by screws 49 to a controlled shaft 50 and having studs 48 receivedby the col lar 47. c

The controller shaft 50 is journalled in a bearing 51 supported by the frame 24 and in a bearing 52 supported by a cover plate 53 which together with the cup 25 and the cover plate 54 cooperate with the frame 24 to provide chamber 55 which houses the lever 48 and mechanism which connects the driving shaft 20 with the cam shaft 40. The cover plate member 53 is integral with a tubular member which provides a pressure or displacement chamber 61 within which a displacement member or piston 62 is slidable. The piston 62 is connected by piston rod 63 and an arm 64 with the controller shaft 50. The lower end of the arm 64 is provided with a slot pin attached to the piston rod 63. The upper end of the arm 64 is attached to the shaft 50 by a screw 66. A screw '67 attaches an indicator 68 to the shaft 50 for the purpose of indicating the degree of advance or retard according to the position of the pointer 68 with reference to certain indexed marks which may be placed upon the outside of the frame 24. The ends of the tubular member or cylinder 60 are closed by plugs 69. Pressure fluid is admitted to the pressure chamber 61 on opposite sides of the piston 62 through ducts 70 and 71 which communicate with ports 70 and 71 respectively provided in the bearing 21 which is non-rotatably supported by the frame 24. Parts of ducts 70 and 71 are provided by the frame 24 and part by the cover member 53.

- The side wall of the bearing 21 opposite the ducts and 71 is provided with two small ducts 72 and 73 communicating with a recess 74 in the frame 24 which is connected by suitable coupling 75 and pipe 76 with the engine combustion chamber, or with one of the combustion chambers in case of a multicylinder engine. The. shaft 20 operates as a valve for controlling the admission of pressure fluid from the ducts 72 and 73 to the ducts 70 and 71. For this purpose the shaft=20 is rovided' with transverse pasadapted respectively to place communication with the duct 72 in communication with the the duct 73 in 71, or the duct duct 70.

All of the shaft bearings, with the excep- 65 for receiving a tion of the ball bearing 41, namely the bearings 21 and 22 for the shaft 20 and the step caring 80 therefor, the bearings 51 and 52 for the shaft 50 and the piston 62 are formed preferably of self-lubricating metal, that is metal that is a substance comprising a porous metallic structure which is saturated with lubricant. This is found desirable in order that the bearing surfaces will be properly lubricated although they may be subjected to relatively high temperature. The bearings 22 and 80 provide a self-lubricating seal for the rotary valve provided by the shaft 20. The frame 24 provides a stuffing box for receiving packing material held in place by a suitable packing gland 82 in order to minimize leakage around the shaft 20.

Assuming that the direction of rotation of the cam 30 is normally clockwise as viewed in Fig. 1, it is evident that clockwise rotation of the cam 30 relative to the shaft 20 will advance the timing of the spark. This relative angular movement between the cam 30 and the shaft 20 will be produced by clockwise rotation of the controller shaft 50,. as viewed in Fig. 1, or counter-clockwise rotation of the lever 64, as viewed in Fig. 4. In other words, a spark will be advanced as the piston 62 is moved toward the right in the cylinder 60; and, vice versa. the spark will be retarded as the piston is moved toward the left in Fig. 4.

Referring to the pressure time diagram shown in Fig. 5, the line X-X is the zero pressure line and distances measured horizontally represent the time of the engine cycle in degrees of crank shaft rotation. The vertical line YY denotes the position of the engine piston at upper dead center of the engine crank shaft. The vertical line ?)6 re resents the instant at which the duct 71 is p aced'in communication. with the engine combustion chamber and the line c(l represents the instant at which communication between the combustion chamber and duct 71 is discontinued. The vertical line e-f represents the instant at which the duct 70 is placed in communication with the combustion chamber and the line g7t repre sents the instant at which communication between the duct 70 and the combustion chamber ceases. The shaded area between the lines (1-6 and 0'al represents the time during which the right hand side or end of the piston 62 is subjected to explosion pressure, and the shaded area between the lines ef and g-h represents the time during which the left hand end of the piston 62 is subjected to explosion pressure. Satisfactory ignition control for certain engines will be provided if the time during which either end of the piston is subjected to explosion pressure corresponds to 19 degrees of crank shaft rotation, and if the time interval between successive openings of the passages 71 istic of combustion when the engine evaluate and t to communication. with the combustion c words, municati 1 degrees communication between the passage 1 and the combustion chamber is discontinued, lit has been found satisfactory to open. the duct ll three degrees before upper dead center" llnv order to explain how the spark is retarded or advanced according to the pres cteristics of combustion, let it be the full line pressure time curve representative ofthe characteris. developing full load and that the broken line curve is representative of combustion when the eng is developing only part load,

lll heu the engine is developing only part load w r a greater degree of sparh advance its permissible than when it is developed in full load. lt will be apparent upon observing where the brolren linecurve crosses the shaded areas that the pressure transmitted through the duct 70 will be greater than that transmitted through he duct 'i'l; hence the pistonbd will he moved toward the right in cylinder 60 in order to advance the timing of ignition. "llhe full line iressure curve representing full load explosion characteristics crosses the shaded area between the lines a-b and c-d'at points representing pressures higher than those occurring when the engine is operating at part load. as represented by the broken line pressure curve.- ft is apparent, therefore, that the right hand end of the piston 62 will be subjected to greater pressures than the left hand end; consequently the piston will be moved toward the left in order to retard the sparlt.

From the foregoing description of the construction and mode of operation of the present invention, it is apparent that by a very simple and economical construction l have provided for the control of ignition timing in accordance with combustion pressure characteristics of the fuel charge in the combustion chamber of the engine. By utilizing the rotating drive shaft of the timer as a rotary valve ll am able to control the admission of pressure fluid to the pressure chamber of the ignition controller without the use of separate slide or poppet valves and separate engine operated cams or similar devices for controlling the movements of the valves.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

it, fin ignition timer and controller therefor comprising a circuit interrupter; an en" gine shaft for operating the interrupter; and means for varying the time relation between the engine cycle and the functioning of the interrupter and including a displacement member movable ina pressurechamber, and means including a rotary valve operated by the shaft, for alternately subjecting opposite ends of the displacement member to engine combustion pressure occurring at predetermined successive intervals du'ring combustion.

2. An ignition timer and controller therefor comprising a circuit interrupter; a rotary cam for operating the interrupter; an engine driven shaft for operating the cam; and means for varying the angular relation of the shaft and cam and including a displacement member movable in a pressure chamber, and

means including a rotary valve operated by the shaft, for alternately subjecting opposite ends of the displacement member to engine combustion pressure occurring at predeter mined successive intervals during combustion.

3, An ignition timer and controller there for comprising a circuit interrupter; an em gine shaft for operating the interrupter; and means for varying the time relation between the engine cycle and the functioning of the interrupter, and including a displacement member movable in a pressure chamber and means for alternately subjecting opposite ends of the displacement member to engine combustion pressure occurring at predetermined successive intervals during combustion, said last named means including a rotary valve provided by ports formed in a journal of said shaft land cooperating with fired ports provided by a bearing for said shaft journal,

a. An ignition timer and controller therefor comprising a circuit interrupter; a rotary cam for operating the interrupter; an engine driven shaft for operating the cam; and means for varying the angular relation of the shaft and cam, and including a displacement member movable in a pressure chamber and means for alternately subjecting opposite ends of the displacement member to engine combustion pressures occurring at predetermined 110 nature,

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